ARCHIVED FORUM -- March 2012 to February 2022READ ONLY FORUM
This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
Hello everyone, it's my first post so, I'd like to introduce myself . My name is Mateusz and I'm from Poland
I've bought not working Beocord 7000 recently. It wasn't turning on, but the problem was mechanically damaged fuse (wire wasn't burnt). After quick fix device started, I've replaced belts and tried to play some tapes, but here comes problem. As shown in the video: link (you may need to set 1080p quality by hand) motor spins but rest of mechanism don't move and it makes weird noises. I noticed that solenoids don't move at all, they aren't stuck and have reasonable resistance.
According to schematics from BO Beocord 6500 version 2 service manual (5 pages free version from web) I've checked timing charts with scope, and all I got was small voltage change (mV). I've also checked MCU reset pin (5V so ok), CASS DET (0V when tape inserted so ok). Next I've found that PROTECT pin is LOW (active), may that be the reason why circuit doesn't start? All semiconductors in this functional group are ok (TR31, 32, 35 D31, 32, 33 etc.) Voltages 5V, 14.8V, 12V 15.5V are also as expected. I don't really understand how protection circuit works (TR38, 37, 36), from my in head calculations PROTECTION net will always be high (pulling MCU pin via TR35 low).
It takes more force than I would expect to turn mechanism wheel, maybe after all those years grease got stiff or smth and MCU somehow detects it?
I would be grateful for any feedback, is there something I missed? Thanks for your time Mateusz
Mroziu:Hello everyone, it's my first post so, I'd like to introduce myself . My name is Mateusz and I'm from Poland I've bought not working Beocord 7000 recently. It wasn't turning on, but the problem was mechanically damaged fuse (wire wasn't burnt). After quick fix device started, I've replaced belts and tried to play some tapes, but here comes problem. As shown in the video: link (you may need to set 1080p quality by hand) motor spins but rest of mechanism don't move and it makes weird noises. I noticed that solenoids don't move at all, they aren't stuck and have reasonable resistance. According to schematics from BO Beocord 6500 version 2 service manual (5 pages free version from web) I've checked timing charts with scope, and all I got was small voltage change (mV). I've also checked MCU reset pin (5V so ok), CASS DET (0V when tape inserted so ok). Next I've found that PROTECT pin is LOW (active), may that be the reason why circuit doesn't start? All semiconductors in this functional group are ok (TR31, 32, 35 D31, 32, 33 etc.) Voltages 5V, 14.8V, 12V 15.5V are also as expected. I don't really understand how protection circuit works (TR38, 37, 36), from my in head calculations PROTECTION net will always be high (pulling MCU pin via TR35 low). It takes more force than I would expect to turn mechanism wheel, maybe after all those years grease got stiff or smth and MCU somehow detects it? I would be grateful for any feedback, is there something I missed? Thanks for your time Mateusz
I can't see your video as it requires login on a different site.Are you sure that the belts are fitted correctly?And did you fit correct belts or something from Ebay, Portugal etc.?
Martin
Thanks for replies.
Vintage_B&O: 1st get the silver membership so you will get the complete service manual. This is essential for a repair.
1st get the silver membership so you will get the complete service manual. This is essential for a repair.
I am certainly going to do it, just wanted to start with electronic schematic. I doubt service manual will have MCU program flow char and will describe how protect circuit works. Or maybe I am wrong.
Dillen: I can't see your video as it requires login on a different site.Are you sure that the belts are fitted correctly?And did you fit correct belts or something from Ebay, Portugal etc.? Martin
I've posted video on YT link. Yes, belts are from Germany and they are fitted correctly. Smaller ones are straightforward and bigger one rotates black wheel and both huge ones. I am curious what is engaged by solenoids? Clutch, head? It is not show in the video, but motor, two big metal wheels and black one spins however tape doesn't move at all. Is it mechanical problem or solenoid?
Mateusz